Hydraulic press



March 13, 1956 D- B. NEFF ETAL HYDRAULIC PRESS 4 Sheets-Sheet 1 FiledDec. 15. 1952 FIG. I

INVENTORS CECIL E-ADAMS y DRY ENEFF HYDRAULIC PRESS 4 Sheets-Sheet 2Filed Dec. 15. 1952 mm 1 F a. 4 fl WWW A w M w Wm, 5 a \\\s LW 5 .w M Hwymgsx, I A \+W- co a 3 2 a Y 5 M 5 7 M a 9/H/% 6 B H a M A d. R II m 0T H" /Il/ 1. n m m w m 3 2 a 4 J 3 H e o o M 0 o W a H w w n w w o n 8 3March 13, 1956 B. NEFF ETAL HYDRAULIC PRESS 4 Sheets-Sheet 5 Filed Dec.15, 1952 FIG. 3

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BY on auzrr Jam/M1? W March 13, 1956 D. B. NEFF ETAL 2,737,928

HYDRAULIC PRESS Filed Dec. 15. 1952 4 Sheets-Sheet 4 FIG.

INVENTORS CECIL E. lDAMS 3y DARBY B.- NEFF MZM United States PatentHYDRAULIC PRESS Darby B. Nell and Cecil E. Adams, Columbus, Ohio,assignors to Denison Engineering Company, Columbus, Ohio This inventionrelates generally to hydraulic apparatus and is more particularlydirected to hydraulic bench presses of the manually controlled type.

An object of this invention is to provide a bench press of small compactdesign having a novel control mechanism which will require the use ofboth hands of the operator during a portion of the cycle of operation torender the press safe for use and then, after the danger period ispassed, the control becomes automatic in operation so that the cyclewill be completed even though the operator may release the manualcontrolling elements.

Another object of the invention is to provide a bench press having aC-frame with base, back and head sections, the base section having acompartment to form a reservoir and receptacle for the major portion ofthe operating mechanism of the press, the construction providing acompact design in which the parts, normally subject to leakage ofhydraulic fluid, are contained in the reservoir and any leakage will beconfined therein thus causing no inconvenience.

Another object of the invention is to provide a hydraulic press having apower cylinder with a movable ram and a control mechanism forcontrolling fluid flow from the pump to the power cylinder, the presshaving manually actuated members for initiating the valve operation andadditional mechanism responsive to predetermined movement of the ram tomaintain valve and power cylinder operation whereby the cycle ofoperation will be automatically completed after having progressed to apredetermined stage. I

A further object of the invention is to provide a hydraulic press havinga power cylinder with a movable ram and a control mechanism, including avalve with a spool and two control knobs which must be operated inunison to move the spool to a predetermined position to initiate forwardoperation of the ram, the control knobs being held in a certain positionto keep the spool in its predetermined position until the ram hasprogressed far enough to actuate a means which causes the application offluid pressure resulting from the forward operation of the ram to thevalve spool to retain it in position to continue the forward operationof the ram; the use of two control knobs requiring the operator toemploy both hands during the dangerous portion of movement of the ramafter which the operators hands may be removed from the control withoutinterrupting the cycle of ram operation. I

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred form of embodiment of the invention isclearly shown.

In the drawings:

Fig. 1 is a vertical sectional view taken through a hydraulic benchpress formed in accordance with the present invention, the internalparts of the press being shown inside elevation;

Fig. 2 is an elevational view of the press taken from the back;

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Fig. 3 is a detail horizontal sectional view taken through line III-IIIof this figure and showing the control mechanism;

Fig. 4 is a vertical sectional view taken through the press on the planeindicated by the line lV--IV of Fig. 3;

Fig. 5 is a detail vertical sectional view taken through a portion ofthe control valve and operating mechanism therefor showing the valve inone position of operation;

Fig. 6 is a similar view showing the valve in another position ofoperation;

Fig. 7 is a detail vertical sectional view taken through the lowerportion of a hydraulic power cylinder used in the press shown in Fig. 1to show a check valve which serves as an unloading valve; and

Fig. 8 is a diagrammatic view of the hydraulic circuit employed in thepress, parts of the hydraulic power cylinder and control valve mechanismtherefor being shown in vertical section.

Referring more particularly to the drawings, the numeral 20 designatesthe hydraulic press forming the present invention. This press includes amodified C-shaped frame 21 which may be cast or otherwise formed fromsuitable metal. This frame includes a base section 22, a back section 23and a head section 24, the latter projecting forwardly from the backsection and overhanging the forwardly projecting portion of the basesection. The head section has a bottom wall 25 which is formed with anopening 26 to receive suitable tooling, not shown, em

ployed when the press is in operation. The back sectionhas a forwardwall 27 from the rear of which projects a lug 28, the purpose of whichwill be set forth hereinafter. Wall 27 also has a slot 39 extendingupwardly in the central portion thereof, the purpose of this slot willalso be set forth hereinafter.

The base section 22 includes the major portion of the operatingmechanism of the press although, as illustrated in Fig. 2, the backsection supports and substantially encloses the driving motor 31 whichis secured to and supported by one of the side walls of the back sectionand the fluid pump 32 which is coupled, as at 33, to the driving shaft34 of the motor 31, the pump 32 being supported by a bracket 35 alsofixed to a side wall of the back section. The base section is formedwith a compartment 36 which forms a reservoir to receive the hydraulicfluid employed to transmit the energy developed by the motor 31 to othermechanism which translates it into motion. This fluid is drawn from thereservoir by the pump 32 through a line 37 and forced through anotherline 33 to the control valve mechanism indicated generally by thenumeral 39. The line 38 also communicates with a relief valve 40 whichis diagrammatically shown in Fig. 8. This relief valve also communicateswith an exhaust line 40A extending back into the reservoir 36. Therelief valve may be located in any desired position. However, in oneembodiment of the invention, it is also located in the reservoir 36 toprevent any possible leakage from being discharged exteriorly of thereservoir. The valve mechanism 39 controls the flow of fluid underpressure from the pump 32 to a power cylinder 41, lines 42 and 43extending from the valve 39 to the upper and lower ends, respectively,of the cylinder 41. As shown in Fig. 1, the valve mechanism 39 and powercylinder 41 are also located within the reservoir 36 formed in the basesection 22. The lines 42 and 43 are formed in the bodies of the valveand cylinder and thus reduce the amount of pipe or tubing used in thepress.

Cylinder 41 receives a piston 44 for longitudinal movement, a ram 45projecting from the piston through the upper end of the power cylinderinto the space between the base and head sections to do useful work. Asthe piston 44 reciprocates in the power cylinder 41, the ram 45 will beprojected into and retracted from the space between the base and headsections of the frame 21. Any suitable tools may be secured to the upperend of the ram 45 when the press is to be operated. The direction andrate of movement of the piston 44 in the power cylinder is controlled bythe position of a valve spool 46 in the casing 47 of the control valvemechanism 39.

Control valve mechanism 39 is of the generally designated four-way type,the casing including a bore 48 for receiving the spool 46, a port 50with which the line 38 leading from the pump 32 communicates, and upperand lower work or cylinder ports 51 and 52, respectively. Port 51communicates with line 42 leading to the upper end of the power cylinder41 while port 52 communicates with line 43 leading to the lower endthereof. Spool 46 is formed with an external groove 53 which serves invarious positions of the spool to establish communication between theinlet port 50 and either of the work ports 51 and 52. Spool 46 is alsoformed with a plurality of internal recesses or passages which connecteither port 51 or 52 with exhaust when the other port is connected withthe inlet port. Spool 46 is normally biased in an upward direction by acoil spring 54 disposed between the inner end of the recess at the lowerend of a spool and a plate 55 secured to the bottom of the casing 47This plate has an opening 56 through which fluid may flow from thecasing to the reservoir. The upper end of the casing 47 has a topsection 57 secured thereto, this section having a passage 58 formedtherein which establishes communication between the upper end of thebore 48 and a downwardly directed tube 59 secured to the cover 56. Tube59 terminates in spaced relation from the bottom wall of the reservoir36.

It will be obvious from the drawing and the description thus far giventhat fluid may flow from either end of the bore 48 into the reservoir.The valve spool 46 .is shown in the position occupied when the press isidle in Figs. 4 and 8. In this position, the groove 53 establishescommunication between the inlet groove 50 and the lower or bottom workgroove 52. Fluid under pressure from the pump 32 is thus directed fromthe groove 50 to the groove 52. This fluid has access to the lower endof the power cylinder through conduit 43 but, inasmuch as the spool 46is blocking the top cylinder groove 51 to prevent exhaust from the upperend of the cylinder and has lateral passages 69 establishingcommunication between the groove 52 and the interior of the spool 46,fluid may flow through the passages 60 and the interior of the spool tothe lower end of the bore 48 from which it may flow from port 56 to theinterior of the reservoir. Since the fluid follows the line of leastresistance, it will flow into the reservoir rather than into the lowerend of the power cylinder.

To actuate the spool 46, the press is provided with a pair of controlknobs 61 shown more particularly in Fig. 3. These control knobs projectfrom the forward wall of the base section, being carried by rods 62which extend through openings in the forward wall of the base andloosely connected at their inner ends with a transversely extendingequalizer bar 63. This bar is pivotally secured at its central point toa link 63A which is, in turn, secured to a bell crank 64 pivoted, as at65', to the top section 57 of the control valve mechanism 40. Crank 64has a rearwardly extending branch 66 which is provided with anadjustable screw 67. This screw is disposed in vertical registrationwith the end of a pushrod 68 pro jccting from the spool 46 through anopening in the top section 57. The pushrod is normally maintained inengagement with the end of screw 67 due to the force exerted on thespool by the spring 54. The expansion of the spring 54 moves the spool46 in an upward direction transmitting this movement to the 'pushrod 68which, in turn, transmits such movement to the bell crank 64 causingmovement thereof about the pivot 65. This movement is transmitted to thecontrol rods 62 forcing these members forwardly through the openings inthe front wall of tion is limited by collars 70 secured to the rods 62.Movement of the spool 46 is also limited by engagement of the upper endthereof with the end of a projection 71 formed on the cover section 57and extending into the upper end of the bore 48. The valve spool isshown in this position in Fig. 5. When the valve spool occupies thisposition, the inlet port 50 is connected by the groove 53 with the topcylinder port 51 and fluid from the pressure source will then bedirected through the line 42 to the upper end of power cylinder 41.

This fluid will be applied to the upper surface of the piston 44 andwill tend to move it, together with the ram 45, in a downward direction.When the piston 44 moves in a downward direction, fluid will bedischarged from the lower end of the power cylinder through line 43 togroove 52 and will flow through the lateral ports 60 and additionallateral ports 72 to the interior of the spool from which it will flow tothe lower end of the bore 48 and through port 56 to the interior of thereservoir. Immediately prior to engaging the bottom wall of the powercylinder, piston 44 will, as shown in Fig. 7, expose a p011 73 extendinglaterally from the power cylinder. This port communicates with a chamber74 which, in turn, communicates with another port 75 leading from thepassage 43. Chamber 74 receives a check valve 76 and a spring 77 whichnormally urges the check valve into position to close the port 73. Whenthe upper end of the power cylinder is connected with the pressuresource and the piston 44 occupies its lowermost position, fluid suppliedto the upper end of the power cylinder may be discharged through thepassages 73, 74, and 75 to the passage 43 from which it may flowdirectly into the reservoir 36. The pump or other pressure generatingmeans will then be unloaded even though the valve spool 46 is inposition to cause the retraction of the piston 44 and ram 45.

The control mechanism also includes a rod 78 termed, in the trade, ashipper rod. This rod is guided in an opening formed in the lug 28 andanother opening formed in the top '57 of the casing 47. This rod extendsdownwardly through the tube 59 which projects from the top member 57.The rod 78 is provided with a collar '80 for engagement with the topmember 57 to limit the downward movement of the rod. It is also providedwith an adjustable, resilient, lost-motion mechanism designatedgenerally by the numeral 81. This mechanism includes a collar 82 whichis adjustably secured to the rod 78 and a collar 83 disposed for slidingmovement on the rod 78. The latter collar is connected with collar 82 bya frame 84 to permit the collar 83 to move toward the collar 82 andlimit the movement in the opposite direction. Between the collars 82 and83, there is provided a coil spring 85. This lost motion connectionpermits the transmission of motion from the ram 45 to the rod 78 throughan arm 86, secured to the ram 45 and projecting rearwardly through theopening 30 to and surrounding the rod 78. When the ram moves in anupward direction, the arm 86 will move likewise. It will engage thecollar 83 causing it to move in an upward direction also. This upwardmovement is transmitted through the spring 85 and collar 82 to the rod78 causing this rod to move upwardly until a resilient disk valve 87engages the lower end of the downwardly projecting tube 59. After thedisk 87 engages the tube, further movement of the arm 86 merely servesto compress the spring 85. The valve 87 is supported on the rod 78 by acollar 88. When the valve engages the tube 59, free flow of exhaustfluid through this tube is resisted to create a back pressure. Someexhaust flow, however, is permitted through a port 90 formed in the tubeadjacent its lower end.

In the operation of the press, the operator engages both control knobs61 and moves them inwardly. This motion is transmitted through the rods62, bar 63, link 63A, and bell crank 64 to the pushrod 68 moving thisred and the spool 46 in a downward direction to the position shown inFig. 6. In this position, spool 46 establishes communi cation betweenthe inlet port 50 and the bottom cylinder port 52. Fluid may then flowfrom the pressure'source through the line 43 to the lower end of thepower cylinder 41. This fluid is applied to the bottom of the piston 44causing this piston and the ram 45 to move in an upward direction. Fluidin the power cylinder 41 above the piston will be exhausted through line42 to groove 51 from which it will flow through lateral ports 91 formedin spool 46 to the interior of the spool and then to the upper end of.the bore 48 from which it will flow through passage 58 and tube 59 tothe interior of thereservoir.

If the operator should release either knob 61 during the upward movementof the ram 45 before the arm 86 engages the collar 83, the spring 54will move the spool 46 upwardly to the position shown in Figs. 4 and 8.In this position, communication between the top cylinder groove or port51 and the ports 91 in spool 46 will be interrupted and the upwardmovement of the ram 45 will be precluded. If both knobs are released,the spool will be moved to the position shown in Fig. 5 in which the topcylinder port 51 will be connected with the source of fluid pressure andfluid will flow to the upper end of the power cylinder to cause theretraction of the ram 45; When the control knobs 61 are held in theirinnermost positions until the ram 45 moves in an upward direction asufiflcient distance to cause the arm '86 to engage the collar 83 andmove the rod 78 in an upward direction causing valve 87 to close thelower end of tube 59, a back pressure will be created on the fluidflowing from the upper end of the power cylinder. This back pressurewill be applied to the upper end of the valve spool 46 and will holdthis spool in its lowermost position shown in Fig. 6.

At this time, knobs 61 may be released without interrupting theoperation of the power cylinder. Since the lost motion mechanism 81 isadjustable on the rod 78, the point at which automatic operation willcommence may be varied depending upon the desires of the manufacturerand user and the tooling with which the press is equipped. It isdesirable to delay the automatic operation until the relatively movabledie elements or other tooling members have approached one anothersufliciently to prevent the operator from inserting his hands or otherbody members therebetween. This feature constitutes a safety measure andrenders the device as foolproof as possible.

When the ram has reached the end of its movement in an upward directionwhich will be determined by the tooling disposed in the press or theengagement of the piston 44 with the upper end of the power cylinder,the ram will stop moving. When this interruption to movement occurs, theflow of exhaust fluid from the upper end of the power cylinder willcease and the back pressure will be dissipated through the port 90. Thespring 54 may then move the valve spool 46 to its uppermost position,assuming the control knobs 61 have been released, to connect the fluidpressure source with the upper end of the power cylinder and effect theretraction of the ram. The force exerted by the ram will be determinedthrough the adjustment of the relief valve 40 in the usual manner. t

While the form of embodiment of the present invention as hereindisclosed constitutes a preferred form, it is to be understood thatother forms might be adopted, all coming within the scope of the claimswhich follow:

We claim:

1. Hydraulic apparatus comprising a source of fluid pressure; areversible fluid motor having a movable element; control mechanismbetween said pressure source and said motor, said control mechanismhaving a reversing valve movable between two extreme positions in whichsaid motor is connected with said pressure source and caused to operatein forward and reverse directions; selectively operated means for movingsaid reversing valve to one extreme position to cause forward operationof said motor; resilient means tending to urge said reversing valve tothe other extreme position to cause said motor to operate in theopposite direction; means responsive to continuous forward movement ofthe movable element of said fluid motor for applying fluid pressure tosaid reversing valve to prevent movement thereof by said resilientmeans; and motion transmitting means actuated by the movable elementofsaid motor at a selected stage of forward operation for rendering saidfluid pressure applying means operative.

2. Hydraulic apparatus comprising a source of fluid pressure; areversible fluid motor having a movable element; control mechanismbetween said pressure source and said motor, said control mechanismhaving a reversing valve movable between two extreme positions in which.

said motor is connected with said pressure source and caused to operatein forward and reverse directions; manually operated means for movingsaid reversing valve to one extreme position to cause forward operationof said motor; resilient means tending to urge said reversing valve tothe other extreme position to cause said motor to operate in theopposite direction; means responsive to continuous forward movement ofthe movable element of said fluid motor for applying fluid pressure tosaid reversing valve to prevent movement thereof by said resilientmeans; and motion transmitting means actuated by the movable element ofsaid motor at a selected stage of forward operation for rendering saidfluid pressure applying means operative.

3. Hydraulic apparatus comprising a source of fluid pressure; areversible fluid motor having a movable element; control mechanismbetween said pressure source and said motor, said control mechanismhaving a reversing valve movable between two extreme positions in whichsaid motor is connected with said pressure source and caused to operatein forward and reverse directions; valve operating means having a pairof actuating elements and motion transmitting means extending betweensaid elements and said reversing valve, movement of both elements tocertain positions being necessary to place said reversing valve in oneextreme position to cause forward motor operation; resilient meanstending to urge said reversing valve to the other extreme position tocause said motor to operate in the opposite direction; means responsiveto continuous forward movement of the movable element of said fluidmotor for applying fluid pressure to said reversing valve to preventmovement thereof by said resilient means; and motion transmitting meansactuated by the movable element of said motor at a selected stage offorward operation for rendering said fluid pressure applying meansoperative.

4. Hydraulic apparatus comprising a source of fluid pressure; areversible fluid motor having a movable element; control mechanismbetween said pressure source and said motor, said control mechanismhaving a reversing valve movable between two extreme positions in Whichsaid motor is connected with said pressure source and caused to operatein forward and reverse directions; valve operating means having apivoted lever; a link pivotally connected intermediate of its ends tosaid lever; a pushrod connected for universal movement to each end ofsaid link; resilient means tending to urge said reversing valve to theother extreme position to cause said motor to operate in the oppositedirection; means operative during continuous forward movement of themovable element of said fluid motor for applying fluid pressure to saidreversing valve to prevent movement thereof by said resilient means; andmotion transmitting means actuated by the movable element of said motorat a selected stage of forward operation for rendering said fluidpressure applying means operative.

5. A hydraulic press comprising a source of fluid pressure; a cylinderhaving a reciprocable ram; control mechanism for'said ram between saidpressure source and said cylinder, said control mechanism having valvemeans with a casing communicating with the pressure source, oppositeends of said cylinder and exhaust; a valve spool in said casing, saidspool being movable between a first position to connect one end of saidcylinder with said pressure source and the other end to exhaust to causeforward operation of said ram and a second position to reverse suchconnections to cause reverse operation of said ram; manually operatedmeans for moving said spool to the first position; resilient meanstending to shift said spool from said first to said second position;fiow resisting means rendered operative by said ram at a selected stageof movement in the forward direction to resist the exhaust flow fromsaid cylinder to create a back pressure; and passage means for applyingsuch back pressure to said spool to resist movement thereof from saidfirst position by said resilient means.

6. In a hydraulic press, a reciprocable ram; control mechanism for saidram having a reversing valve; actuating means for said reversing valve,said means being operative to dispose said valve in a position to causesaid ram to move in one direction, spring means tending to move saidreversing valve to a second position to cause said ram to move in theopposite direction; means for resisting the movement of said valve tosaid second position by said spring means, said resisting means havingmeans responsive to continuous movement of said ram in said onedirection to maintain a hydraulic pressure; and means for applying suchpressure to said valve.

7. In a hydraulic press, a reciprocable ram; control mechanism for saidram having a reversing valve; actuating means for said reversing valve,said means being operative to dispose said valve in a position to causesaid ram to move in one direction, spring means tending to move saidreversing valve to a second position to cause said ram to move in theopposite direction; means for resisting the movement of said valve tosaid second position by said spring means, said resisting means 'havingmeans responsive to continuous movement of said ram in said onedirection to maintain a hydraulic pressure; means for applying suchpressure to said valve; and a bleed passage for dissipating saidhydraulic pressure when movement of said ram in said one direction isdiscontinued to permit movement of said valve by said spring means.

8. In a hydraulic press, a reciprocable ram; control mechanism for saidram having a reversing valve; actuating means for said reversing valve,said means being operative to dispose said valve in a position to causesaid ram to move in one direction, spring means tending to move saidreversing valve to a second position to cause said ram to move in theopposite direction; passage means for fluid displaced by movement ofsaid ram in said one direction; means for opposing fluid fiow from saidpassage to create a back pressure, said valve being exposed to such backpressure to oppose movement of said valve by said spring means; andmotion transmitting means actuated by said ram at a predetermined stageof movement to render said fluid flow opposing means operative.

9. In a hydraulic press, a reciprocable ram; control mechanism for saidram having a reversing valve; actuating means for said reversing valve,said means being operative to dispose said valve in a position to causesaid ram to move in one direction; means automatically tending to movesaid reversing valve to a second position to cause said ram to move inthe opposite direction; passage means for fluid displaced by movement ofsaid ram in said one direction; means for opposing fluid flow from saidpassage means to create a back pressure in said passage means, saidvalve being exposed to such back pressure to resist movement by saidautomatic means while said ram ,is moving in said one direction; motiontransmitting means actuated by said ram at a predetermined stage ofmovement thereof to render said fiow opposing means operative; and bleedpassage means for dissipating the back pressure when movement of saidram in said direction is discontinued to permit said valve to move tosaid second position and cause movement of said ram in the oppositedirection.

R ferences {Iiteei in the file of this patent UNITED STATES PATENTS1,676,866 Maury July 10, 1928 1,829,184 Daly Oct. 27, 1931 2,169,470Miller Aug. 15, 1939 2,473,167 Mills June 14, 1949 2,512,731 Adams June27, 1950 FOREIGN PATENTS 403,154 Great Britain Dec. 27, 1933

